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Cowl Cheeks ???

PlaneBuilderBill

PlaneBuilderBill

Well Known Member
Now that I'm smack in the middle of the cowl install, I have a question that I know somebody has the answer to.
Where the top and bottom parts of the cowl lay on the fiberglass cheek extension ledge (about 1" wide), do they just fit tight and lay there, or do you fasten them with camlocks or something similar?

Thanks in advance for the response.
 
Bill,

I fit mine without anything there as per drawing 43. I suppose it wouldn't hurt to install a flush camlock if you didn't have a tight fit.
 
Yes

Hi Bill,
We just went through this recently on my buddy's -4. You need a couple of nut plates or camlocks there because the loose sides will bulge out at speed. We placed them close together, one for the upper and one for the lower corners

Be careful to have the cheeks and cowl located so that the cheeks don't cover up the screws that hold the forward skin on.

Regards,
Pierre
 
Hmmmm . . .

I thought the hinge that holds the top and bottom half together would pretty much keep those parts flush against the cheeks. If I understand the plans correctly, it looks like the hinge extends back far enough (basically all the way back to the cheeks) to keep the overlapping parts tight over the cheek extension, if that makes sense. The plans also talk about extending the hinge pin into the front "bulkhead of the cheek" as well.

Any thoughts or experiences with this?
 
Nope.....

Rick RV-4 said:
Hmmmm . . .

I thought the hinge that holds the top and bottom half together would pretty much keep those parts flush against the cheeks. If I understand the plans correctly, it looks like the hinge extends back far enough (basically all the way back to the cheeks) to keep the overlapping parts tight over the cheek extension, if that makes sense. The plans also talk about extending the hinge pin into the front "bulkhead of the cheek" as well.

Any thoughts or experiences with this?
Click to expand...

I think that the hinge pin would not be inside far enough. I just looked at it and it looks like you'd be drill into the outer shell of the cheek and not inside it (where the air space is) :confused: if I explain myself. Here's a picture of the tendency of the cowl to lay away from the cheek.
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Regards,
Pierre
 
Cowl Cheek Fasteners

Bill...

Look on Randy Lervold's RV-3 site for a good photo of fasteners in the cowl cheeks. The photo is in the "Airframe Construction" section; scroll down to the "Finish Kit" area. http:///www.romeolima.com/rv3works/

The cowl cheeks on my RV-3 don't have fasteners or rivets, and there is a noticeable bulge of the cheeks on the left side at cruise speed. I'm adding some rivets or fasteners at the next condition inspection.

...Joe Lofton
 
Cowl cheek firewalls?

A related question to what has gone before.

Should I put a 'f'irewall' across the front of the cowl cheek? It would be complicated to make it tight with the side skin. What is normal here?

I also dont see there is enough room to extend the hinge pins into the cowl cheeks since they will be in the very edge. Should I just cut them off short?

Thanks,
 
Cowl cheek firewall?

Apologies, I know I asked this before, but I got no answer. What do folk normally do with the hole in the front of the cowl cheek? I dont want to add weight, but without a firewall there the entire firewall appears to be compromised. However VANS supply no SS to seal it off. Please advise.

Thanks
 
Cowl Cheek Bulkheads

Steve...

Vans sells aluminum cowl cheek bulkheads (F-365-R and F-365-L). I bought a set because my RV-3 was built without them and I thought it a good idea to have a little more protection in case of under-cowl fire/smoke. Most of my instrument connections are down the cheeks and through the sidewall instead of through the firewall. However, the ones I bought didn't fit - maybe my cheeks were custom-made.

At Oshkosh I asked one of the Vans guys (Tom?) about them. He replied that they are not needed for structural reasons, but could be fabricated and added with pop rivets and sealant.

...Joe
 
Guys

Just a thought on fastening the cowl to the cheek extensions. I did this originally on my four, and after a hundred hours or so the rivets holding the cheek extensions to the fuselage started to work loose, and I've had to replace some of them with Pop rivets. The fiberglass developed some cracks as well. I stopped using the screws that went to plate nuts on the extensions, filled and painted the holes in the cowl and no more problems. Works just fine with no attachments to the extensions. The cowl that tends to move around a bit working on the firmly riveted extensions seems to be the cause of the cracks, loose rivets.

Joe Hine
C-FYTQ RV4
Fredericton, N.B.
 
Use Proseal on the rivet line

Joe Hine said:
Just a thought on fastening the cowl to the cheek extensions. I did this originally on my four, and after a hundred hours or so the rivets holding the cheek extensions to the fuselage started to work loose, and I've had to replace some of them with Pop rivets. The fiberglass developed some cracks as well. I stopped using the screws that went to plate nuts on the extensions, filled and painted the holes in the cowl and no more problems. Works just fine with no attachments to the extensions. The cowl that tends to move around a bit working on the firmly riveted extensions seems to be the cause of the cracks, loose rivets.
Joe Hine
C-FYTQ RV4
Fredericton, N.B.
Click to expand...
I used Proseal (in addition to rivets) on the rivet line where the cowl cheek extentions attach to the fuselage... don't think I'll ever have any issue and none so far.
 
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